In the field of orthopedic surgery it is common to rejoin broken bones. The success of the surgical procedure often depends on the ability to reaproximate the fractured bones, the amount of compression achieved between the bone fragments, and the ability to sustain that compression over a period of time. If the surgeon is unable to bring the bone fragments into close contact, a gap will exist between the bone fragments and the bone tissue will need to fill that gap before complete healing can take place. Furthermore, gaps between bone fragments that are too large allow motion to occur between the bone fragments, disrupting the healing tissue and thus slowing the healing process. Optimal healing requires that the bone fragments be in close contact with each other, and for a compressive load to be applied and maintained between the bone fragments. Compressive strain between bone fragments has been found to accelerate the healing process in accordance with Wolf's Law.
Broken bones can be rejoined using staples. Staples are formed from a plurality of legs (typically two legs, though sometimes more) connected together by a bridge. Staples are typically manufactured from either stainless steel alloys, titanium alloys or Nitinol, a shape memory alloy. The staples are inserted into pre-drilled holes on either side of the fracture site.
While these staples are designed to bring the bone fragments into close contact and to generate a compressive load between the bone fragments, the staples do not always succeed in accomplishing this objective. It is widely reported that the compressive load of staples dissipates rapidly as the bone relaxes and remodels around the legs of the staples.
Thus there exists a clinical need for fixation devices that are able to bring bone fragments into close proximity with each other, generate a compressive load, and maintain that compressive load for a prolonged period of time while healing occurs.
Moreover, existing staples have bridges that are fixed in size, shape, and dimension, while each procedure presents a unique anatomical requirement (which is set by a combination of indication and patient-specific anatomy). Existing staples with fixed shape and dimension bridges will often sit “proud” of the cortical bone, resulting in irritated and inflamed adjacent soft tissue and, in some cases, bursitis.
Thus there also exists a clinical need for a staple with a malleable bridge that may be bent so as to conform to the unique anatomical structure of each patient and sit flush on the cortical surface of the bone.